I'm based in Thailand, and a member of the THAI Airways program. I'm getting ready to come to the USA, and need to book some domestic economy travel on CO and UA on a multi-city itinerary. I want to dodge certain fare classes from CO and UA that don't yield mileage credit back to THAI. Is there a way to do that on either of their websites? I see that on CO's website I can search specifically for certain fare classes, but it looks to me like I might need to book and purchase as separate one-ways for each segment because it doesn't let me control what I'm looking for on each segment, but rather just the overall search. It's further complicated because it shows code shares also (and they map differently between CO and UA as to what yields credit at THAI.) Purchasing separate one-ways might in turn bump the total price up (compared to buying a multi-city A to B to C to A itinerary.)

I do have the KVS Tool I can use to search out these available fare buckets. I'm just wondering about a reasonable way to book them all together?